Why colouring packing so important???
This is because product pH and exposure to light, oxygen and temperature after manufacture can all adversely affect shelflife so when we use the dark colour package its will preserve products shelflife.

What are the natura colouring??
Nature-identical colouring products, such as beta-carotene, canthaxathin, apocarotenal, some astaxathin and some lycopene.

Why synthetic products colour are more prefer to use??
Because they are more able to withstand rigorous processing systems, high temperatures and extreme pHs that can have adverse effects on naturally derived colorants. Synthetic products also tend to be more economical and far less likely to affect finished-product flavor.